2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/59215The set of all efects on a Hilbert space has an affine structure (it is a convex set) as well as a multiplicative structure (it can be equipped with the so-called Jordan triple product). In this paper we describe the corresponding automorphisms of that set.9 pages. To appear in Lett. Math. PhysOperator AlgebrasMathematical Physicstext